Tracing anthropogenic trace element contamination of natural and human
systems in the South Pacific using honey bees as a key biomarker
Abstract
New Caledonia’s Ni deposits account for ~ 8.2% of the
world’s production of mined nickel, with a major smelting facility
located in the country’s capital city of Nouméa (population 100,000).
There are emerging concerns relating to contamination of human and
natural ecosystems from dust and soil contamination from mineral
processing emissions, which started the late 19th century. There is
widespread reuse of Ni smelter slag in the city for multiple uses (e.g.
building aggregate, erosion control, added to soil and surface as
‘gravel’) in the city, which contains up to 2% Cr. This study provides
the first integrated environmental analysis of the impact of the smelter
and associated anthropogenic trace element contamination of Noumea’s
natural and human environments. To assess the impacts from smelting,
hundreds of trace element data points were collected across Nouméa in a
variety of matrices. These include natural rocks and deep soils, top
soils, deposited dusts, residential garden soils, indoor vacuum dusts,
honey bees and honey produced within the city’s urban environment.
Rocks, soils and exterior and interior vacuum dusts were analysed for
their trace element concentrations using X-ray fluorescence at
< 100 locations within a 3 km radius of Nouméa’s Ni smelter.
Samples of bees (live and dead), honey, soil and deposited dust were
collected at 15 beehive locations across the Noumea area to ascertain if
and what contaminants are being remobilized in dust, contaminating both
food and ecological systems. Natural/background values were assessed
using two bee hive locations, distant from the smelter, along with
analysis of rocks and sub-surface soils from the main geological strata
present in the city. Preliminary environmental data show that
anthropogenic contaminants Cr, Ni, Pb and S exceed natural values by up
to 8, 2.5, 10 and 15 times in different matrices. Analysis shows that
CrVI is present in the slag and surface dusts (x̅ total Cr in deposited
dust = 450 µg/m2) and that more than 60% of Ni dust loadings are
> 1000 µg/m2 (x̅ Ni in dust = 2,400 µg/m2). The presentation
will detail trace element concentrations in live and dead bees and
corresponding honey samples and evaluate the data against corresponding
levels measured in the adjoining environment to assess the
remobilization and recycling of anthropogenic contaminants.